Hmmm, I'm not sure that cache.size() call and that warning are related, because cache.size() is computed based only on the elements residing in memory.

That warning could come from loading all, or partially the elements in the JDBM store and size being called by that. Dunno where that would happen in your env though.

So, at first glance, you shouldn't worry about it, but if you can find out, with a breakpoint or something, how that warning appears, we might be able to help further to see if it's something to worry about or not.